Fix NullReferenceException when opening split view after enabling the "change margin" setting.

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs

@@ -207,7 +207,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			textView.Services.AddService(typeof(IBookmarkMargin), iconBarManager);
 			codeEditorView.TextArea.LeftMargins.Insert(0, new IconBarMargin(iconBarManager));
 			
-			if (CodeEditorOptions.Instance.EnableChangeMarkerMargin) {
+			if (changeWatcher != null) {
 				codeEditorView.TextArea.LeftMargins.Add(new ChangeMarkerMargin(changeWatcher));
 			}
 			

src/Main/Base/Project/Src/Project/AbstractProject.cs

@@ -597,6 +597,7 @@ namespace ICSharpCode.SharpDevelop.Project
 		{
 		}
 		
+		[Browsable(false)]
 		public Properties ProjectSpecificProperties {
 			get; protected set;
 		}

src/Main/Base/Project/Src/Project/Solution/Solution.cs

@@ -34,6 +34,7 @@ namespace ICSharpCode.SharpDevelop.Project
 			this.changeWatcher = changeWatcher;
 		}
 		
+		[BrowsableAttribute(false)]
 		public Microsoft.Build.Evaluation.ProjectCollection MSBuildProjectCollection { get; private set; }
 		
 		#region Enumerate projects/folders